Technical Field
Embodiments of the present invention generally relate to the field of display technology, and in particular, relate to a method and a system of flattening a surface formed by sealant of a packaging cover plate, and a packaging method.
Description of the Related Art
In the field of current display devices, performance of a display device is more focused on. In particular, for an organic light emitting diode OLED display device, lifetime becomes a critical factor. However, the main reason for this defect is in that a metal cathode of low work function and an organic functional layer in the device are very sensitive to water and oxygen in environment and easily interact with oxygen and water, resulting in degraded performance of the device. Therefore, packaging process of the OLED device becomes critical process for improving lifetime of the OLED display device.
However, since material of sealant used in packaging process is mainly composed of UV curing adhesive glue and glass glue, which glass glue is composed of inorganic glass material and organic matter (organic solvent and resin), a screen printing method is generally applied to screen print glass glue onto a package substrate, and then organic matter in the glass glue is removed after pre-sintering process and high temperature sintering process. In actual production process, the high temperature sintering process will destroy structure of a surface formed by sealant so that the surface is uneven, resulting in many visible steps. Due to the uneven thickness of the sealant, laser energy required for melting the sealant is not constant, and stress easily occurs during packaging process; meanwhile, sealability is insufficient after packaging due to the visible steps.